I have been wondering this of late - How did we get to the point where higher voltages like 14.1 or higher voltage is being run on slot car tracks?

When you run a battery like an 8D, it is comprised of 6 cells of lead acid technology. This technology will produce 2.17 to 2.21 volts of DC when properly maintained. In telephone companies, they have huge battery plants that supply the necessary voltage to keep the telephone switching systems functioning during power outages. Have you ever noticed that you can call the power company to ask when the power will be back on when your home is without electricity?

Some of these batteries are HUGE and trust me, quite expensive. To keep costs down, maintenance is something that is kept very strict control over. Each of the cells is read on a weekly or bi-weekly basis, recorded and sent into the responsible manager of the power systems. Along with the voltages being read, hydrometer readings and water levels are recorded. If the cell readings are not in the requited range of 2.17 and 2.21 volts, maintenance starts tight then and there. Typically the chargers are switched from "Float" to "Equalize". This higher voltage will 'shock' the batteries and help bring them back into spec.

Why don't the telephone companies run this higher voltage all the time? Simply put, it destroys the batteries by causing excessive heat in the plates of the batteries. This excessive heat causes the plates to warp which degrades the ability of the battery to hold a charge. The telephone companies typically keep a battery string up and running for 20 years.

Now we look at slot car batteries. If you maintain that 2.17 to 2.21 volts, you should read a fully charged battery at 13.02 to 13.26 volts. Remember, that if you are the high end of the reading, your batteries will not last as long as they do at 13.02 volts.

At one of the raceways we were having issues with a brand of motor that was all of a sudden reliability issues. One of our racers changed 4 motors during the course of a race. By accident, the charger was switched off one weekend. During the race no one went through a motor, the racing action was a bit slower - perhaps a couple of tenths and most of us agreed the racing action was cleaner and keener.

So I still have to ask, why do we insist on running more voltage on our tracks then manufacturers reccomend and then complain about the life expectancy of motors and such?

At a recent race during a preliminary trip, it was noted that the track was a bit tricky to get around. When we measured the voltage it was at 14.1 volts. We asked the track owner if the voltage could be dropped. Basically the charger was turned off and the track voltage was at 12.9 volts at the start of the race and also at the end of the race. A properly maintained 8D battery can handle 25 amps for 460 minutes. So a race that has Falcon 7 motors with 8 cars running draws less then that amount of power. With the race running for 24 minutes, you hardly scratch the surface of the ability of the battery's capacity.

If you really want to get 'high tech' on battery systems for slot car racing, all you need to do is set up the charger so the AC to the charger is turned off when track power is turned on and back on when track power is turned off. During a typical retro race you run 3 minutes of on and 2 minutes of off for each heat. At the end of the race you have run about 25 amps for 8 minutes without the charger being on.

Now if you consider that most tracks that have 8D batteries have two of them wired in parallel, then you can run the races twice as long or up to 50 amps for 460 minutes.

In addition to a higher voltage, I'm sure if you check you will find a small amount of AC ripple from the charger. This adds to heat as well.

When I came back to slots in the late '80s after over fifteen years away, it seemed that many tracks had "qualifying voltage" pushing near 16v. I guess for track records? Made no sense to me, you should qualify at the voltage you race at.

But then they used to use special qualifying motors in NASCAR many years ago, didn't they?

Because of public demand we organized the ´92 European Championships in Kuopio with batteries capable to 17v. Never seen drivers so hurried to wind chokes on empty cans (and I had to buy a Koford external resistor controller to replace my early '70s Parma triple barrel).

After G27 it was pretty easy to gather consensus to drop to about 14v - it was good enough to smash the cars in the tricky corners.

Slot racing just gets "hung" with a standard. The standard for charging a 12 volt source is to use about 14 volts. This causes no damage to the mulitude of equiment using these voltages.

Slot racing comes along and wants the standards rewritten to preserve their motors. It ain't gonna be!

But slot racers can demand the slot motors be changed to milder winds that can operate at 14 volts. The first Mabuchi 16D motors were designed to operate on Revell's 18 volt power supplies. It's the racers that wanted hotter winds.

Slot racers aren't going to change the world standard of 14 volts. They can request milder motors that operate with higher voltage. Of course, as Philippe states, the cars will be a couple tenths slower. And the motor suppliers will resist, as they will sell less motors.

Indeed that was the stupidest thing they did. It also is killing open-class racing. Amazing of imbecility in reasoning. Will it now kill Retro racing???

Since the power is the same for everyone, I would also imagine the consistency between motor types would also be closer.

Do you agree?

Marty,

It would the same situation when you have higher voltage in a way with a bit more extreme figures, but it is clear that higher voltage plus AC ripple kills our slot car motors regardless of which type.

Hence, any SANE raceway owner would be well advised to take things in his own hands and get devices to regulate track power to straight 12 volt (and not even that "magical" 13.6 or "fully charged batteries") and keep it there. Such a raceway would increase its customers base right there.

Just to give you an idea of the diff: we ran a D3 retro Pro race last Saturday art BP. The track record on basically 14 volts and a bit of ripple at the Checkpoint Cup last January is 3.24", most guys ran in the 3.6" range and several motors (the normally bullet-proof PS/X12) went poof. Saturday we ran just about 12.5 volt on tired batteries, and the speeds were 3.6" to 3.8". My own motor ran so cool I was amazed, and the loaner D3 Coupe from my friend Bryan Warmack ran virtually COLD (Falcon 7).

Voltage was pretty much a local option with no standards from the very beginning.Blame the drag racers and Bob Herrick when he was the USRA tech inspector for sanctification of high voltage.

From the USRA Rulebook:

"In all USRA events, qualifying voltage for all classes will be limited to a maximum of 16.0 volts, and race voltage will be limited to a maximum of 14.3 volts."

He wrote the 16v max into the rules to control voltage for drag racing, thinking no-one would be crazy enough to use it as a way to justify 16v on a road course... silly optimist.

Errrr, ummmmmmm, not Bob Herrick's fault in any way... just so you know as you weren't there... here is what happened back then...

As more and more tracks wanted to be the world's fastest... a situation at a race in Chicago where they were qualifying on 22 volts or pretty close to that, a piece of a exploding armature that almost caused loss of eyesight to a turn marshal, the USRA took action and came up with a voltage "limit" for USRA racing only as there had never been any limits before then.

After much discussion and meetings among USRA officials and manufacturers... the 14/16 rule came about and again... it's for USRA racing only and NO raceway has to follow USRA voltage rules.

Any raceway is free to do what they want with voltage today or tomorrow... the USRA or Bob Herrick has no control over that... never had. never will.

Raceway owners/management control the voltage... NO ONE else. Voltage ONLY has to be controlled at USRA events.

Well since Scott is chiming in on this, how hard is this to do? What damage is done to the batteries/track/etc? I would like to know how much this would slow down cars on a big track. Would this change cars to being full punch at some of the swoopy kings?

Do you know the difference between education and experience? Education is when you read the fine print; experience is what you get when you don't.

Just like you say the race car is a complete package, so are track systems. I have had them all. The wiring harness is as important as the power source and many times, more so.

I hated the charging between heats and turning the charger off when the heat started, you would have a surface charge for 20 seconds and then back to the battery reserve the rest of the heat, unless you have multiple battery sets to suck the surface charge into the passive set for the heat it will be very up and down. When batteries are new even with a charger on the ripple is negligible, I have had an oscilloscope on the track to check this. As the battery wears out, the ripple will go up.

Many times when the car runs hot the return is just not of sufficient size although the math says it is.

I have used every kind of battery on the planet, 8Ds probably being the worst to use because it's just not correct for the application but they are reasonable and when new really pump out the voltage. Many can tell you the stories of the Nuc power plant batteries I had in the '90s. No charger at all, one day, 120 entries and they lost one-tenth of 1 volt at the end of the day, from Group 12 to opens. They were individual cells 2.2 volts each and weighed in at 80 pounds apiece. There were 48 of them under the pit tables and six 8Ds inside the infield. LOL. No charger required.

Well, since Scott is chiming in on this, how hard is this to do? What damage is done to the batteries, track, etc? I would like to know how much this would slow down cars on a big track. Would this change cars to being full punch at some of the swoopy Kings?

At 12 VDC you could use a rubber band as a driver on our King on six of eight lanes.

When we visited a track for a SoCal USRA race in the early '80s, we always had to ask about the power. "Was the big charger going to be on during practice? Quals? Races?" That would determine what winds we would use. Some of us had adopted a 30A Tophat diode for e-drop and ripple reduction.

So,What is the easiest, least costly, most reliable way to control/reduce voltage fro a track owner?

Straight power supplies would do what you are looking for perhaps adding 1 or 2 farad of capacitance, but most raceways would choke on the price of a quality power supplies capable of supplying the clean current required (lack of leakage ripple) that is so detrimental to any type of DC device.

The reason you see cheap power supplies and battery chargers under tracks is cause they are cheap and by attaching them to a battery, there is some cleaning of the lousy power those things are kicking out. Luckily the batteries do OK with that type of power but our motors do not. For whatever reason, very few raceways using poor power supplies seem to have wired their systems (batteries and power supplies) in such a way as to isolate the track from the power supplies output.

Hard to tell from a distance but sounds like a voltage drop situation. Voltage drop is proportional to load so a lighter drawing mill wouldn't cause as much drop as one that draws a heavier current. As the PS tries to run, voltage drops causing the mill to run slower and draw more current, more current equals more heat.

Could be as simple as loose connections or as involved as undersized wiring or possibly not enough taps.

Is that easy to fix? Or is it a major rewiring? I am clueless on track wiring..

As Roman says without seeing it, it would be tough to diagnose. First thoughts are the same as Ron, too small a return, it might only have two taps? Some will split the taps, pos/neg, and call it four when in reality it's still just two. This is pretty common problem (too small a return) on most track wiring.

How does just one car run on the track? How much does the track back up when all eight cars are on there running? Most tracks will back up about 2 tenths from running a single car to eight lanes being used.

Although the Puppy Dog is a low amp motor, I will bet you would be amazed at the actual amp draw it calls for on the track. Hook up an amp meter between the controller and the post someday.

Mark to answer the question at hand, how did we get to high voltages, that's a pretty easy one really.

In the late 80's, slot cars began a resurgence and wing racing was king. All the track were trying to get fast times at their raceways to get the racers in the shop. It was an evil circle. If R-Geo went 2.3, then Chicago and New York wanted to 2.1 etc. Voltage and batteries were getting built up, chargers were left on for racing and qualifying, all for the fastest lap times. Euro Kings were just beginning to come into vogue and tracks were built with more banking to go faster, and hold more volts. Really destroyed open motors. LOL. I think Tri-state USRA was the first to install a voltage limit in their series. Then the mishap in Chitown, Ron spoke of. Although the arm would have probably come apart on 14 also, just drilled too deep.

So it escalated to just wanting to go faster and faster. Wing cars were the dominant cars at the time. When the USRA adopted voltage limits that ended the voltage wars and the tracks were just made faster to keep the times dropping until you have 2010.................

Well, my answer pre-dates the 80's. The concept of voltages being introduced above 12 v goes back to drag racing as was pointed out by Tony P. So, while there may be a newer version, it all really started with getting padlocks to go faster.

I think Marty more meant about general slot tracks, not drag strips in his initial question?

Mark to answer the question at hand, how did we get to high voltages, that's a pretty easy one really.

In the late 80's, slot cars began a resurgence and wing racing was king. All the track were trying to get fast times at their raceways to get the racers in the shop. It was an evil circle. If R-Geo went 2.3, then Chicago and New York wanted to 2.1 etc. Voltage and batteries were getting built up, chargers were left on for racing and qualifying, all for the fastest lap times. Euro Kings were just beginning to come into vogue and tracks were built with more banking to go faster, and hold more volts. Really destroyed open motors. LOL. I think Tri-state USRA was the first to install a voltage limit in their series. Then the mishap in Chitown, Ron spoke of. Although the arm would have probably come apart on 14 also, just drilled too deep.

Yea and while the track styles were changing..... don't forget "long" timers/tracks that were racing for 5 and half minute heats on the slower tracks while the faster tracks were racing 5 minute heats.

Then there was a few "fast" timers being used for qualifying.

Then there was one track in Michigan were they had switches up in the race directors booth where they could switch any lane from 13-14 volts to 18 volts depending on who was on what lane.... make your buddy go faster or make your enemy burn up.

When I first started to read this thread, I thought it might be homeset oriented. The issue there is that to have 12 volts DC under two or more car loads, those wimpy wall wart power supplies have to be rated at 14 volts without load.

I have long promoted the basic goal of model slotcars to be raced on automotive battery (12 VDC) as a standard. The reality is that the meter shows our "standard" 12 VDC to be a little higher at 13.2-13.4 VDC. I have no problem with that either. What I HAVE seen problems with is 1)the need for speed. 2)power source standards. 3)changing technology.
The need for speed is a human trait that CAN be habit forming - and we have addition treatment centers for that. Changing technology is an area that I have witnessed over the years. Many of the vintage tracks of the 1960's used voltage stepping power supplies, but had limited wattage and a poor understanding of the needs of our form of racing.
When I had the opportunity to dicsect the Vintage 140 track that I bought in the 1990's, I found one 18 gauge power tap and two 4 amp power supplies - one for each of the four lanes. I rewired that track with three taps of 12 gauge wire and an 8D battery. I remember power surges galore on that track in the 1960's - and we only had one motor rule: RUN WHAT YOU BRUNG. In the 1980s and early 1990's we raced with the big automotive (and some trickle type) battery chargers on the car and truck batteries. Rarely did a race end without at least one fried motor and plume of smoke. The raceway owners also could not keep fluids in the batteries without weekly fill-ups and annual battery replacements.
Battery chargers have largely been replaced (or SHOULD BE) by now with the RV industry AC/DC power converters of the IOTA/Bulldog variety that give a much cleaner power and stable charging rate for lead acid batteries. Many local building codes and inspectors have banned the use of liquid batteries in stores due to the charger issues of Hydrogen out-gassing that are eliminated by the use of these RV chargers - and we CAN control the output voltage under 14 VDC. Many raceways have gone sans battery, but not low amperage by using the even newer technology of the Server power supply where 300 amp/ 5 VDC units are wired in series to provide an adjustable DC voltage.
I have also used one to three Farad Capacitors on tracks from the car audio industry and feel that they reduce motor damage issues from the power supplies that have limited built-in capacitance.

Ban chokes and motor changes and the rest will tend to work itself out. The Speed Crazed Morons alway push past reason if they can. Then they are reluctant to call it a mistake because by then they have developed the technology to cope with their insanity and want to preserve their investments and not lose their technological edge.

The light at the end of the tunnel is almost always a train.Mike Boemker

Another standard track detail that I have developed and promote is the use of a fourth post on the driver panel.

The GRAY post is a three volt choke formed by making a four diode series chain from the white post. I use the basic three amp diodes which also make a current limiter and works well for all 30 gauge armatures or smaller for rentals and little kids just learning to make laps. Just hook up a standard controller with the white clip on the gray and let them drive. If they keep the car on the track, they can move up to the white post. It is A whole lot cheaper than having a special set of rental controllers...and more consistent than a lane by lane power controller.

It's funny....... as the voltage came up and the AC ripple Power Supplies came into "vogue" the MFG's adapted and made their products better to handle the extra juice... I am talking about 14.5 volts here. I spent countless hours at Parma testing and figuring out how to get the Asian stuff to live through that better, Mura did it, P-S did it, Koford did it, etc etc.

Now here we are again with another Asian motor that can't handle the voltage and now some scream for voltage changes.

Once we can get "uniform" voltage rules or whatever you want to call them and all the raceways follow them, then it could be better, but good luck with getting that to happen.

Back around 1979-81 both Momence and Centerville was where the speed crazed morons really upped the game. Multiple semi truck batteries and big chargers are what I remember. Every pro wanted to be the first to do a sub 3 second time. Then in the mid 80's when Grand raceway opened 2.9 was a G 27 time.

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Maybe they didn't do it in the 70's, but they sure as hell started it on the road course King tracks in the mid 80's when all of you were absent and this was before slot drag racing got started up again.

Yea and while the track styles were changing..... don't forget "long" timers/tracks that were racing for 5 and half minute heats on the slower tracks while the faster tracks were racing 5 minute heats.

Then there was a few "fast" timers being used for qualifying.

Then there was one track in Michigan were they had switches up in the race directors booth where they could switch any lane from 13-14 volts to 18 volts depending on who was on what lane.... make your buddy go faster or make your enemy burn up.

Ron,Your history of slots is impeccable.

I remember one of the long timer guys. When you would approach him and ask why he was timing his 3 minuteheats 20 seconds long, his answer was because he checked his dark room timer and found out it was 2 seconds fast every 3 minutes so he set his timer long to compensate. When I said "OK, then set your timer 2 seconds long, not 20", he looked at melike I was speaking Martian.

I remember the variable power deal in Michigan. I didn't think he could vary it from lane to lane.I was later told I was an intended target. Despite an all-star field, I don't think Watson, Pfeiffer or Laster made the main because of the goofy conditions.I spent a whole lot of time spinning my choke dial but I'm pretty sure I won by at least 70 laps oversome handsome young racer running for Parma.